读取英文单词，按顺序排列（C++学习题目）

1. Implement a function that counting word frequency. It reads an English article from an user-specified txt file(article.txt) and counts their number. Those exclusive words should not be counted. Output the words and counts to 2 files. One(3_1_1out.txt) is in lexicographic order, and the other (3_1_2out.txt) is in descending frequency order.